Assessing bone regeneration potential of 3D scaffold-free cell pellets from periodontal ligament and bone marrow stem cells.

BACKGROUND

Bone defects pose a significant clinical challenge in clinical treatment, where stem cell-based tissue engineering strategies have emerged as a promising approach for bone regeneration. Notably, accumulating evidence suggests that scaffold-free three-dimensional cell pellets demonstrate therapeutic potential through direct implantation into bone defects area.

METHODS

Two types of stem cells were isolated from bone and tooth, then cultured separately. Surface markers (CD34, CD45, CD90, CD105, CD146, STRO-1) were analyzed by flow cytometry. Bone marrow-derived and dental-derived CPs were cultured in ascorbic acid-supplemented growth medium. Histological morphology from CS to CP was examined through H&E staining. Cell pellets' biological properties were assessed in vitro via immunofluorescence, qPCR, and Western blot, and bone regeneration was evaluated using rat calvarial defect models.

RESULTS

We demonstrated comparable morphology and immunophenotype between BMSCs and PDLSCs. H&E staining and TUNEL assays revealed tightly organized histological structures and low apoptosis rates in 5-day cultured cell pellets. Immunofluorescence analysis showed no significant differences in COL-1 or early osteogenic marker ALP between PDLSC-CP and BMSC-CP; however, BMSC-CP exhibited higher osteoblast-related BSP expression, whereas PDLSC-CP displayed elevated bone remodeling-associated OPN levels. Consistent trends were observed in qPCR and Western blot analyses. In rat calvarial defect models, both CP types induced significant bone formation, with BMSC-CP demonstrating enhanced osteogenic capacity compared to PDLSC-CP.

CONCLUSION

Both BMSC-CPs and PDLSC-CPs demonstrate osteogenic potential in scaffold-free 3D environments, whereas standardized controls and mechanistic investigations are required to establish their distinct therapeutic advantages.